Problems based on Money

Q) The coach of cricket team buys 7 bats and 6 balls for Rs. 3800.

Later, she buys 3 bats and 5 balls for Rs. 1750.

Find the cost of each bat and ball.

What are we suppose to find?

Soln.

Let the cost of 1 bat be Rs. x and 1 ball be Rs. y

Cost of 1 bat is Rs. x

Hence cost of 7 bats = Rs. 7x

Similarly cost of 6 balls = Rs 6y

According to the first condition,

7x

+

6y

= 3800

........(i)

According to the first condition,

3x

+

5y

= 1750

........(ii)

Solve the equations by either Substitution or Elimination Method

x = 500

y

=

Substituting x = 500 in (ii)

50

∴ Cost of 1 bat is Rs. 500 and 1 ball is Rs. 50

Q) The coach of cricket team buys 3 bats and 6 balls for Rs. 3900.

Later, she buys another bat and 2 more balls for Rs. 1300.

Represent algebraically and graphically

Soln.

Let the cost of 1 bat be Rs. x and 1 ball be Rs. y

Cost of 1 bat is Rs. x

Hence cost of 3 bats = Rs. 3x

Similarly cost of 6 balls = Rs 6y

According to the first condition,

3x

+

6y

= 3900

.....(i)

According to the Second condition,

4x

+

8y

= 1300

.....(ii)

Total number of bats = 3 + 1 = 4

Hence cost of 4 bats = Rs. 4x

Similarly cost of 8 balls = Rs 8y

Dividing throughout by 3

x

+

2y

= 1300

Dividing throughout by 4

x

+

2y

= 325

x + 2y = 1300

x

y

(x, y)

0

650

(0,650)

1300

0

(1300, 0)

x

y

(x, y)

2

160

(2,160)

325

0

(325, 0)

x + 2y = 325

100

200

300

400

500

600

0

200

700

(1300, 0)

(0, 650)

Scale

On X axis 1 cm = Rs. 200

On Y axis 1 cm = Rs. 50

X

Y

x + 2y = 1300

x + 2y = 325

600

400

1000

800

1400

1200

(2, 160)

(325, 0)

Now let us represent graphically by drawing the graph

Represent algebraically means we just need to form the equations

No need to solve the equations as the question is just to represent algebraically and graphically